Water softener



Patented Nov. 6, 1934 WATER SOFIENER,

Robert E. Zinn, Chicago Hei Victor Chemical Works,

ration of Illinois No Drawing.

Claims.

This invention relates to an improved water softener and, more particularly, to a water softener consisting of thin flakes of alkali metal pyrophosphates or metaphosphates, with adhering 5 alkali metal salts.

In my co congealing said substances, discharging the material in ribbon-like partially congealed form from the rolls, and completing congelation thereof.

Flakes so produced may be used as water softeners, and produce salts of calcium magnesium, etc., which are sufliciently soluble so as to produce no precipitate in thetreated water. It is often desirable, however, to add other alkali metal salts to meta or pyrophosphates or mixtures thereof. For instance, with certain types of hard water, the pyro or metaphosphates will not reduce the hardness to zero by the soap test, but with an added alkali metal salt such as trisodium ortho phosphate, or sodium carbonate, the hardness can be readily reduced to zero without any precipitation. It has now been discovered that the flakes of phosphatic material so prepared may so readily be incorporated with other alkali metal salts by powdering such salts and mixing them with the flakes. The flakes are then agitated and are sprayed with a fine mist of water in a definite amount so that no substantial solution of the flakes occurs. Th out by using a normally hydrated alkali metal salt in anhydrous or partially anhydrous condition, and using suflicient moisture to cause adherence of the crystals, but not substantially more than is necessary to permit the salt to regain its normal hydrated form. Preferably only enough is used to partially rehydrate the salt, and the range of 80% of the amount required for this purpose is generally preferred.

As an example of this process, thin flakes of alkali pyro or metaphosphates or mixtures thereof, are produced having a glossy appearance, but spotted with very small crystals of the adhering salt. The salt has the appearance of being fused into the surface of the flakes.

The percentage of alkali metal salt added to the pyro or metaphosphate may; be'adjusted as desired, up to of the resulting flake, without causing any hard water precipitate when used 5 as a water softener in hard water.

Application Sep Serial No. 688,2

As an example of phosphate flakes were with the process of my Serial No. 688,267 were pl ghts, 111., assignor to hicago, Ill., a cometember 5, 1933,

the invention, sodium metaprepared in accordance co-pending application, aced in a mixer similar to an ordinary concrete mixer, the desired amount of trisodium phosphate mono-hydrate in powdered form was dusted into the mixer with the metaphosphate fiakes, and the two were thoroughly mixed. After the mixing was complete, a fine spray of water was sprayed into the mixer. The trisodium phosphate became afl'ixed to the flakes and took up the wate tion without any r as water of hydraappreciable solution of the flakes. In a specific instance water suflicient to produce about 8 or 9 molecules of water of crystallization was used, as

against 12 required to completely rehydrate.

It is obvious that producing flakes of other means may be used for this character or to produce the permanent adherence of the added salt. For example, the flakes may be first sprayed with moisture and then dusted with a partially or wholly anhydrous salt. Likewise, a solution of the added salt dissolved in its water of crystallization may be sprayed onto the surface of the flakes and crystallized thereon when cooled. It

is also possible to produce the flakes by using more than the amount of water described, but

it is preferred not flakes may be c produced in this to do so inasmuch as the onsiderably damaged. Flakes manner will not cake, are almost instantly soluble in water, are readily handled for domestic a position of the throughout, since, would be the case b nd commercial use, and the commaterial remains uniform there is no segregation as etween a powder and a flake.

The trisodium phosphate is also low in phosphate content, ye effect so that there t it contributes as much softening is a saving in cost.

Alkali metal hydroxides may also be used, but it is preferred not to produce a water softener in flake form in this case, because of the deliquescent character of drated" as used in th is meant a substance tially or wholly dehydra As set forth in Serial No. 688,267,

the hydroxides. By dehye claims of this application, which has been either parted.

my co-pending application filed September 5, 1933, the d in accordance with the have a thickness of the ch. This may be varied 'mits, but in general, the

no unnecessary Iimitatio should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

I claim:

1. A water softener comprising a flake having a thickness of the order of .001 of an inch substantially of a compound of the class consistin of alkali metal meta and pyrophosphates and mixtures thereof, and having spotted on the surface thereof a minor proportion of crystals of a compound of the class consisting of alkali metal orthophosphates and carbonates.

2. A water softener comprising a flake having a thickness of the order of .001 of an inch substantially of alkali metabmetaphosphate, and

having spotted on the surface thereof a minor proportion of crystals of a compound of the class consisting of alkali metal orthophosphates and carbonates.

3. A water softener as set forth in claim 2 in which the crystals are substantially of alkali metal orthophosphate.

4. A water softener as set forth in claim 2 in which the crystals are substantially of alkali metal carbonate.

5. A water softener comprising a flake having a thickness of the order of .001 of an inch substantially of sodium metaphosphate and having spotted on the surface thereof a minor proportion of crystals of sodium carbonate.

ROBERT E. ZINN. 

